Pulse shaper



Feb. 24, 1970 a. TAPLIN ET AL 3,496,956

PULSE SHAPER Original Filed June 25, 1963 MOVHBLE PIS TON PUL owzn-r/o/v 74b arms/v7- (VAR/ABLE VOLUME) A T TOENEY United States Patent 0 US. Cl. 13781.5 4 Claims ABSTRACT OF THE DISCLOSURE A pure fluid device for producing fluid pulses of optimum shape using triggering pulses of arbitrary and possibly unacceptable shape characteristics. This device has application where logic is transmitted by pulse frequency and pulse shape characteristics are to be held uniform to prevent errors when pulse averaging is utilized.

Cross references The present invention is a division of co-pending US. application Ser. No. 290,527, filed June 25, 1963, entitled Fluid Pulse Control, now United States Letters Patent 3,392,739.

Background This invention relates to pure fluid stream interaction amplifiers, sometimes termed fluidics.

Basic pure fluid stream interaction amplifiers are known and illustrated in such prior patents as US. Patent 3,016,- 063 and 3,053,276. The present invention extends the known techniques to provide a device for the specific purpose of converting pure fluid pulses of arbitrary shape into pure, fluid pulses of optimum shape which can thereby be usefully used in other types of pure fluid devices. The shaping or re-shaping of pulses is flequired whenever an existing pulse form is not proper for an intended use. Thus, when either a generated pulse does not have optimum shape because of the characteristic of the pulse generator or when a pulse shape has been distorted because of attenuation over a length of transmission line, it is desired that the pulse be re-shaped to be of uniform amplitude and duration.

Summary The present invention provides a pure fluid device with the ability to, in effect, convert a pure fluid pulse of arbitrary shape characteristics into a pure fluid pulse having optimum shape characteristics as may be predetermined by the relative sizes of the device and the ultimate use of the pulses. This allows re-shaping of attenuated pulses and shaping of signal or control pulse of possibly unacceptable shape.

Brief description of drawing The drawing is a schematic representation of a pulse shaping or re-shaping device which utilizes as a trigger a signal pulse of arbitrary configuration to generate an output pulse Whose characteristics can be predetermined.

Description of the preferred embodiment In the drawing there is shown a pulse shaper for utilizing an existing signal pulse to trigger the generation of a new output pulse of determined amplitude and duration, but having the same frequency as the triggering pulse. The pulse shaper includes a high pressure supply chamber 10, P connected by transmission line 12 to main supply jet 14. The high pressure supply stream ejected from jet 14 traverses receiving chamber 16 and normally flows 3,496,956 Patented Feb. 24, 1970 out through vent passage 18 to the atmosphere or the like. A triggering pulse which is a distorted signal pulse is supplied by passage 20, having a control jet 22 ejecting into receiving chamber 16 generally transverse to the main supply stream. Output passage 24 is arranged generally obliquely to vent passage 18 and has a receiving port 26 opening into receiving chamber 16 slightly offset from the main supply stream in a direction opposite that of control jet 22. By design, a small depression or volume 28 is formed in the side wall of output passage 24 downstream of receiving port 26. A triggering pulse, supplied by passage 20, is ejected by control jet 22 and causes upward deflection of the main supply stream from vent passage 18 to output passage 24. As the main supply stream flows through output passage 24, its rapid velocity aspirates fluid from the volume or region provided by depression 28, causing a low pressure region which holds the main supply stream in its deflected condition even after the triggering pulse has stopped. Thus, once deflected, the supply stream due to passage design has the capability of attaching itself to the wall of output passage 24 somewhat analogous to an electrical push-pull switch having a holding coil which, when once activated, hold the switch in its activated state until a deactivating signal is supplied. It has been found that the ability of the main stream to attach itself to a wall in a deflected condition requires generally intermediate main stream velocities. If velocity is either excessive or too low, a suflicient degree of turbulence required to aspirate fluid in region 28 does not exist.

The reset signal for restoring the main supply stream from its deflected state back to vent passage 18 is supplied by a feedback circuit comprised of passage 30 opening into output passage 24 at a spaced distance downstream of region 28. Passage 30 contains a restriction 32 and exhausts into chamber 34. A movable piston 36, which may equivalently be an adjustable diaphragm or bellows, forms one wall of chamber 34 to provide a means for adjusting the chamber volume. Feedback passage 38, having a restriction 40, connects chamber 34 with feedback control jet 42 which ejects into receiving chamber 16 generally transverse to the main supply stream.

The pulse generation and shaping operation proceeds as follows. An acceptable trigger pulse is received in passage 20, is ejected from control jet 22 and deflects the main stream flow into output passage 24. A triggering pulse is acceptable if the magnitude is sulficient or large enough to initiate main stream deflection, the detailed form of the trigger pulse is not important and generally is anticipated to be in a considerably-distorted or degenerated condition. Once deflected, the main stream attaches itself to the output passage wall by means of the aspirating effect on region 28. Part of the mainstream flow is diverted through passage 30 into the feedback path com prised of restrictions 32 and 40 and the volume of chamber 34. A time delay in the feedback path is induced by the time required to fill the volume of chamber 34 and build the pressure in the feedback line to a sufiiciently high value whereby when ejected by feedback control jet 42, it restores or resets the deflected main stream to its original flow path out vent 18, thus stopping the flow out of output passage 24. The output pulse thus produced started when the trigger pulse was received and lasted until the delayed feedback signal reset the flow. The output pulse length is proportional to the feedback delay which may be varied by adjustment of the volume in chamber 34 by means of piston 36.

We claim:

1. A fluidic pulse shaper comprising:

a pressurized source of main supply fluid;

a main supply jet in communication with said source and adapted to eject a substantially continuous main fluid stream;

a fluid interaction region into which said main fluid stream is ejected;

a. first passage having a first receiving port in said interaction region;

said main supply jet, fluid interaction region and first passage cooperative to normally cause said main fluid stream to be received by said first passage;

a signal control jet arranged intermediate said main supply jet and said first receiving port;

said control jet operative to receive control fluid signals and to eject said control fluid generally transverse said main fluid stream thereby diverting said main fluid stream away from said first receiving port;

a second passage having a second receiving port in said interaction region;

said second receiving port operative to receive said main fluid stream when diverted by control fluid ejected by said control jet;

said second passage and said interaction region cooperative to maintain said main fluid stream in a diverted flow condition when said control fluid signal terminates; and

a feedback system interconnecting said second passage and said fluid interaction region operative to extract a portion of said diverted main fluid stream and to cause said diverted main fluid stream to be re-diverted toward said first passage whereby the flow of said main fluid stream in said second passage downstream of said feedback system exhibits a predetermined duration.

2. The pulse shaper as claimed in claim 1 wherein said feedback system comprises:

an input passage branching off of said second passage and operative to receive a small portion of said diverted main fluid stream;

a feedback control passage having a feedback jet arranged generally in opposition to said control jet; and

a chamber defining a volume interconnecting said input passage and said feedback control passage operative to establish a time delay in said feedback system.

3. A pulse shaper as claimed in claim 2 wherein said means defining a given volume includes a movable wall member defining one wall of said volume, said wall member being adjustable to vary said given volume and alter said time delay.

4. A pulse shaper as claimed in claim 2 wherein said chamber provides a continuous flow path from said input passage to said feedback control passage so that the pulse shaper does not require moving parts in order to operate.

References Cited UNITED STATES PATENTS 3,072,147 1/1963 Allen et al. 1378l.5 XR 3,158,166 11/1964 Warren 13781.5 3,175,569 3/1965 Somers 137-815 3,204,652 9/1965 Bauer 137--81.5 3,295,543 1/1967 Zalmanzon 13781.5 3,396,619 8/1968 Bowles et al. 137--81.5 XR

SAMUEL SCOTT, Primary Examiner 

